1. Field of the Invention
The present invention relates to a platen roller fixing structure and a printer including the platen roller fixing structure.
2. Description of the Related Art
A printer that feeds a printing medium on which printing is to be performed, performs printing on the printing medium, and cuts the printing medium after printing is illustrated in, for example, Japanese Laid-Open Patent Application No. 2004-98625. However, Japanese Laid-Open Patent Application No. 2004-98625 discloses no fixing structure for fixing a platen roller used for feeding the printing medium to a predetermined position relative to a print head.
Here, such a fixing structure is included in a printer 51 as illustrated in FIG. 1. In the printer 51, a platen roller 52 and a print head 53 form a printing part. The platen roller 52 is disposed on a paper holder cover 56, which is a movable part connected via a hinge 55 to a main frame 54, which is a body part. The print head 53, a platen roller receiving part 57, and a platen roller fixing spring 58 are disposed on the main frame 54.
Referring to FIG. 1, the printer 51 accommodates a roll R of a printing medium P such as paper. The printer 51 includes a battery B, which serves as a power supply for the printer 51. The printer 51 further includes a paper holder cover lock 59. The paper holder cover lock 59 holds an end portion of the paper holder cover 56 from the exterior side after the paper holder cover 56 is moved from an open position indicated by a broken line to a closed position indicated by a solid line.
FIG. 1 illustrates a cross section of the printer 51 perpendicular to the center axis line of the platen roller 52 and including the platen roller receiving part 57. In this cross section, the platen roller fixing spring 58 has an L-letter shape and has its long-side portion fixed to the main frame 54 using an appropriate technique such as screwing, bonding, insert molding, or the like.
The short-side portion of the platen roller fixing spring 58 is inclined in an inward direction relative to and toward the circumferential clockwise approach path of the platen roller 52 at the time of closing the paper holder cover 56. Further, the long-side portion of the platen roller fixing spring 58 is inclined in an inward direction relative to and toward the circumferential counterclockwise leaving path of the platen roller 52 at the time of opening the paper holder cover 56.
In this printer 51, after the platen roller 52 is housed in the platen roller receiving part 57 after the paper holder cover 56 is closed, the long-side portion of the platen roller fixing spring 58 holds and fixes the platen roller 52 to the platen roller receiving part 57 with the elastic force of the platen roller fixing spring 58, unless an operating force greater than or equal to a certain magnitude is exerted on the leaving path side.